日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 S (固体地球科学) » S-SS 地震学

[S-SS14] 地震発生の物理・断層のレオロジー

2019年5月29日(水) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:岡崎 啓史(海洋研究開発機構)、向吉 秀樹(島根大学大学院総合理工学研究科地球資源環境学領域)、野田 博之(京都大学防災研究所)、吉田 圭佑(東北大学理学研究科附属地震噴火予知研究観測センター)

[SSS14-P16] Effect of Wear Process on Earthquake Recurrence

*Wang Jeen-Hwa1 (1.Academia Sinica)

キーワード:Earthquake、Recurrence、Slip、Friction、Viscosity、Wear

Earthquake recurrence is studied from the temporal variation in slip through numerical simulations based on the normalized form of equation of motion of a one-body spring-slider model with thermal-pressurized slip-weakening friction and viscosity. The wear process, whose effect is included in the friction law, is also taken into account in this study. The main parameters are the normalized characteristic displacement, Uc, of the friction law and the normalized damping coefficient (to represent viscosity), η. Define TR, D, and tD to be the recurrence time of events, the final slip of an event, and the duration time of an event, respectively. Simulation results show that TR increases when Uc decreases or η increases; D and tD decrease with increasing η; and tD increases with Uc. The time- and slip-predictable model can describe the temporal variation in cumulative slip. When the wear process is considered, the thickness of slip zone, h which depends on the cumulated slip, S(t)=ΣD(t), i.e., h(t)=CS(t) (C=a dimensionless increasing rate of h with S) is an important parameter influencing TR and D. Uc is a function of h and thus depends on cumulated slip, ΣU, with an increasing rate of C. In the computational time period, the wear process influences the recurrence of events and such an effect increases with C when C>0.0001. When viscosity is present, the effect due to wear process becomes stronger. Both TR and D decrease when the fault becomes more mature, thus suggesting that it is more difficult to produce large earthquakes along a fault when it becomes more mature. Neither the time-predictable model nor the slip-predictable one can describe the temporal variation in cumulative slip of earthquakes under the wear process with large C.